


rule of threes

by zannen



Category: EXO (Band), Red Velvet (K-pop Band)
Genre: Alternate Universe - Non-Famous, Established Relationship, F/M, Fluff, Friends to Lovers, Implied Seulrene, M/M, Polyamory, Polyamory Negotiations, Threesome - F/M/M
Language: English
Status: Completed
Published: 2018-01-22
Updated: 2018-01-22
Packaged: 2019-03-08 02:03:13
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,921
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13448187
Author URL: https://archiveofourown.org/users/zannen/pseuds/zannen
Summary: Baekhyun doesn't have feelings for his best friend, and even if he did, said friend definitely wouldn't reciprocate. His girlfriend seems to think otherwise.





	rule of threes

**Author's Note:**

  * For [xenobotanist](https://archiveofourown.org/users/xenobotanist/gifts).



> The M rating is for talk of facesitting and gratuitous use of the word "pussy." There's no actual smut here. I was too lazy to write any. :')
> 
> Also, I'm dedicating this to Allie, since she was the reason I even bothered throwing together this self-indulgent little thing however long ago I wrote it. ♡

“You know, Seulgi called me the other day to ask for a favor.”

“Oh yeah?” Baekhyun looks up from the strawberry tartlet he’s been poking at with his fork. He’s eaten two already, and while he knows he _could_ stomach a third, he isn’t sure if it’s a good idea. This is all Kyungsoo’s fault for being so obscenely skilled at baking. “I didn’t know you guys talked.”

It would be a stretch to say that Baekhyun’s best friend and girlfriend were close at all. It’s not that they don’t get along—they’re both too nice not to like each other—but most of their interactions are politely neutral, neither one of them seeming to know what to talk about with the other. A lot of awkward but friendly silence. The fact that Seulgi even has Kyungsoo’s number comes as a surprise to Baekhyun.

“She calls me sometimes for my opinion before she buys you presents,” says Kyungsoo. “And for things like this, apparently.”

“Things like what?” asks Baekhyun.

Kyungsoo seems to hesitate, tugging at the sleeve of his sweater in what Baekhyun knows to be a nervous habit of his. “She asked if I would… have a threesome with the two of you.”

Baekhyun’s fork clatters loudly to his plate. His stomach is full of angry wasps, his skin all pins and needles. He flounders, trying to remember how to form words with his mouth. “I.” He chokes a little, then tries again. “You’re joking, right?”

Kyungsoo’s frown says he absolutely isn’t joking. “I said I’d need to talk about it with you first. She knows we have a history, so it’s—”

“A history,” Baekhyun echoes. “We have a history?”

Now the frown is slightly judgmental. “What else would you call it?”

“Just—nothing, we made out and jerked each other off one time when we were drunk! We even said we wouldn’t talk about it again! And now you’re breaking the rules and talking about it!” Baekhyun doesn’t even mean to sound so hysterical about it, but this is all fucking weird and he’s anxious and mortified and wants to die.

“So you don’t want to,” says Kyungsoo.

“I didn’t say that, I’m just.” Baekhyun pushes his plate out of the way so he can sink down and rest his forehead on the table, groaning. “Fuck, this is so weird.”

“If you think it would make things too awkward,” says Kyungsoo, “then I can tell her it’s not a good idea.”

Baekhyun takes a deep breath. The fact that Kyungsoo apparently doesn’t mind either way makes him want to repeatedly hit his head against the solid wood. He didn’t ask for this. He’s a good person, he doesn’t deserve to suffer through the idea of the guy he’s been repressing his intensely homoerotic feelings for having sex with the woman he’s kind of definitely in love with—and right in front of him, no less. God. Talk about giving a guy a complex.

He lifts his head, glances up at Kyungsoo apprehensively, mumbles, “Can’t believe my girlfriend didn’t tell me she wanted to fuck my best friend.”

Kyungsoo frowns harder, then raises his eyebrows. “Baekhyun,” he says, “she wants me to fuck _you_.”

“Oh.” Baekhyun blinks. “Wait, you lost me.”

“She said you’ve talked about it before. In terms of other men being involved.” Kyungsoo’s tone is a little flustered. “You told her you wanted—”

“Okay, please don’t finish that sentence,” Baekhyun interrupts, face burning. “Whatever you were gonna say is probably true, but it’s also probably something I said in the middle of dirty talk, and I don’t need any of that repeated back to me ever because I’m filthy and horny and shameful.”

“You’re all of those things, yeah,” says Kyungsoo, “but that’s not the point.”

“So what is the point, Soo?”

“That… I’ll do it if you want to.” Kyungsoo licks his lips. “But it can’t be another thing that we promise not to talk about.”

Baekhyun isn’t sure what that means. He doesn’t know what _any_ of this means, honestly. This all feels like some kind of waking dream, except it’s not even a realistic one, because what are the chances of him being offered the chance to have sex with the two people he cares about most at the same time? He did say before that he’s a good person, but he’s not _that_ good a person. He’d have to be some kind of saint to deserve this.

“I mean.” Baekhyun clears his throat awkwardly. “How, uh, how do you feel about it? Do you actually wanna do it?”

“I kind of thought that was implied when I said I’d have sex with you,” Kyungsoo says drily.

“But that’s not the same as—”

“I do, Baekhyun. I want to.”

It takes a moment for Baekhyun to figure out how to respond to that. His pulse is hammering away in his ears. “Okay, so that’s. A thing.” He pauses. “Well. Um. I do, too.”

Something like relief seems to wash over Kyungsoo’s face. “Okay. Then we’ll do it.”

“Yeah. We’ll—have a threesome. Together. With my girlfriend.” Just saying the words out loud is enough to break him a little bit.

Kyungsoo squints. “Are you okay?”

“Not even a little bit,” Baekhyun confesses. “There’s a lot to unpack here.”

“Should we talk about it? I don’t—”

“Nope, no talking necessary, don’t worry about it.” Baekhyun practically jumps out of his chair. “I just have to talk to Seulgi about some things, and I’ll—she—uh. We’ll get back to you. About logistics and things.”

“Okay?” says Kyungsoo, radiating confusion.

“So yeah. I’m gonna.” Baekhyun gestures vaguely to the door and turns to go.

“Wait.” He freezes mid-step and turns back to Kyungsoo, who’s gotten up from his seat as well. “Let me pack up some of the pastries for you to take home. I baked too many, and you’re more likely to finish them than I am.”

The more time Baekhyun spends here, with Kyungsoo looking all adorable and earnest in front of him, the more he feels like he’s going to violently hemorrhage and die. “Okay,” he says weakly. “Sure, go ahead.”

He waits, fidgeting anxiously and trying his best to look at anything but Kyungsoo, except then he realizes he’s being weird, so he looks too _much_ at Kyungsoo, and that’s weird, too. This is terrible, he thinks. He doesn’t know what he’s supposed to do when they’re actually naked in front of each other.

Moments later, Kyungsoo hands him a plastic storage container, and Baekhyun chokes out a “Thanks.” Then there’s silence, and he feels like he’s supposed to say or do something; he just isn’t sure what. “So. Uh.”

“Would it make things less weird if I kissed you, or would that just make it worse?” asks Kyungsoo.

“I—is that allowed?” says Baekhyun, voice cracking embarrassingly.

Kyungsoo’s lips twitch. “I have your girlfriend’s permission, I promise.”

Baekhyun hesitates, then just nods, not trusting himself to speak.

The touch of Kyungsoo’s hand against the back of his neck is electrifying. Baekhyun reaches out blindly to set aside the storage container full of tartlets and mini quiches, then leans in to meet Kyungsoo halfway, ignoring the hammering in his chest and letting his eyes fall shut.

The world doesn’t end when their lips connect. Baekhyun doesn’t die from the light pressure of Kyungsoo’s mouth, or the tingle of Kyungsoo’s fingers threading up through his hair, or the maybe-too-comfortable feeling of having his hands on either side of Kyungsoo’s waist. Then, almost too soon, it’s over, and Kyungsoo pulls back, though not before Baekhyun manages to steal another fleeting peck on the lips.

He opens his eyes, and Kyungsoo’s smiling, which is a little terrible. This entire situation is terrible, actually.

“Okay, that was nice,” says Baekhyun. “I need to leave, like, immediately I think.”

“Okay,” says Kyungsoo, still grinning.

“Okay.” A beat. “Thanks for the food.”

“No problem.”

“Alright. So I’ll just.” He grabs the container clumsily, almost drops it, and hurries out of the apartment in such a daze he almost forgets to even put his shoes back on on his way out.

  


  


Seulgi’s curled up on her couch with her laptop when Baekhyun lets himself into her apartment. They’re at the point where he doesn’t need to text her before coming over—which is lucky, since she has a habit of leaving her phone in the pocket of her hoodie and forgetting about it, so the likelihood of her even seeing his texts is almost nonexistent most days. Busyness can make her a little absentminded. In an endearing way, though.

She looks up from her screen and gives him a little smile, reaching up with one hand to take off her clunky headphones and let them hang around her neck. “Hey,” she says. “I was gonna order pizza after I finished tending to my crops.”

It takes a second for him to figure out what she means before he remembers she’s been on a _Stardew Valley_ kick recently. “I can call it in for you,” he says. “Large sausage and mushroom?”

“Love you,” she sing-songs in confirmation, grinning sunnily.

It takes all of thirty seconds to take care of the order, since Seulgi’s a regular and they know her by name. Once Baekhyun’s done he shuffles over to join her on the couch, head coming to rest on her shoulder, watching her take care of her little pixel farm. She smells like lavender soap and fresh linens. Kyungsoo hadn’t smelled like that. He’d been shortbread and cologne and—Kyungsoo.

“Tired?” asks Seulgi.

“Kinda,” says Baekhyun. Then, “Why’d you proposition Kyungsoo for a threesome without telling me about it first?”

“Oh. Umm.” She freezes for a second, then, with a few quick keystrokes, exits out of the game and closes her laptop. “What happened?”

He sits up and sees her nervous expression, teeth biting down on her lower lip and gaze avoidant.

“I freaked out and we kissed and then I freaked out more and went home,” he says.

He can just see the tension leave her body. “Oh, good. Not about the freaking out,” she adds, “but the kissing means everything’s fine, right?”

“Seulgi.”

She sighs. “Sorry. I just didn’t think either of you would make a move without a little push, you know?” At his blank look, she continues, “I thought if I talked to Kyungsoo about it first and then had him talk to you, everything would go smoother.”

“Wait, wait,” he says. “What do you mean, ‘make a move’? Why would we make any moves?”

Brow furrowing, she says, “Are you purposely being dense, or did you really not realize?”

“Not realize _what?_ ”

“That you have feelings for each other,” she says, like it’s the most obvious thing in the world. “Even Kyungsoo knew. He apologized to me for it, actually. It was sweet.”

Baekhyun just stares, speechless. He can’t deny the feelings part, because she’s not wrong, but the thought of there being some mutuality to those feelings, and Kyungsoo knowing about it and not saying anything, is killing him a little inside.

“Anyway, if it would make you more comfortable, I don’t have to be there,” she says. “I just suggested the threesome thing because I didn’t want you to feel like you were cheating, and I thought it would be like a nice present for you, maybe.” She shrugs, casually, like this is a perfectly normal thing to talk about.

“Do you _want_ to be there?” he asks. “Like. Wouldn’t it be weird for you? An entire other guy who isn’t me would be seeing you naked. And you’d have to see his dick. And still be able to look him in the eye afterward.”

“I was a little nervous about the whole idea at first,” she says, “but I think it could be a fun thing to try.”

“Fun,” he says. “Sure.” He pauses. “Okay, so what the fuck reason was he giving me for why you suggested a threesome, ‘cause it didn’t sound like it had anything to do with you playing matchmaker.”

She looks confused for a few seconds before realization seems to dawn. “Was it the thing you said about wanting me to sit on your face while—”

“You told him that?” Baekhyun cuts in, having realized with horror exactly what she’s talking about.

“It seemed relevant?” she says with a nervous, apologetic smile. “I didn’t think he’d mention that, though. I just wanted to give both of you an out so you wouldn’t have to confess your feelings if you weren’t up for it. And your threesome fantasies were a good excuse.” Another shrug, this time sheepish.

“Okay, but.” He holds back a sigh. “Now everything’s complicated. We can’t just have a threesome without there being any confession thing, or—god, we probably shouldn’t at all if there are feelings involved, huh?”

“Why not?”

“Well, that’s kind of… leading him on?”

“How?” she asks. “Wouldn’t you just date after that?”

And then Baekhyun realizes: “Oh. This is a polyamory kinda thing.”

Now Seulgi’s the speechless one. Rendered incapable of responding to Baekhyun’s stupidity, probably.

“I thought you wanted us to fuck to get it out of our systems or something,” he says, feeling like he should explain himself.

“That’s. Ridiculous,” she says.

“Yeah, now that I say it out loud, it sounds really dumb.”

“You should probably go tell him you’re in love with him,” she says.

“I can’t,” he says. “The pizza’s on its way.”

A pause.

“Okay,” she says slowly, “you can have some pizza and _then_ go tell your best friend you’re in love with him.”

“Okay. That’s fair.”

She looks like she has something else to say, but just shakes her head with a little smile. She reaches up and brushes some of the hair from his forehead, asking softly, “How are you feeling?” There’s a certain sweetness in the way she looks at him, open and sincere and kind, full of warmth.

No one in the world really deserves Seulgi, Baekhyun thinks. Him especially. Still, he’s lucky she chose him anyway, even though there are a million better, less complicated guys out there. Guys who don’t have stupid feelings for their best friend, probably.

“Nervous,” he mumbles.

“What do you think’s gonna happen when you talk to him?”

He doesn’t know. He’s a little afraid to find out, really. Afraid of what could change from all of this.

“I don’t need to talk to him today.” He sinks down, buries his face against Seulgi’s shoulder, curls against her side and tries to make himself as small as possible. “It can wait.”

“Are you sure?”

“It’s fine,” he says, voice muffled by Seulgi’s shirt. “We’re gonna fuck and pretend that feelings aren’t a thing and that me and you didn’t have this conversation. And then I’ll talk to him after.”

She doesn’t tell him that’s a terrible idea, even though he thinks it definitely is. All she says is, “Up to you.” Mildly and without judgment.

“You’re the best girlfriend,” he says, because it’s true. “Best in the entire universe.”

She lets out one of her flustered-sounding giggles. “Stop, you’re such a suck-up.”

He winds his arms around her waist, holds her to him, loves her indescribably.

And right now, he thinks that’s enough.

  


  


They all just lie in silence for a moment, sticky with sweat and unspeakable things. The whole room reeks of sex. Baekhyun stretches his legs in front of him on the sheets and grins lazily, boneless and satisfied.

“Gonna pee,” Seulgi murmurs. She holds a section of bedsheet to her body as she sits up, and the sudden modesty almost makes Baekhyun laugh.

“Taking the sheets with you?” he says.

She pauses. “Um.”

“I’m not looking, if it helps,” says Kyungsoo. And sure enough, when Baekhyun glances over he sees that Kyungsoo’s eyes are closed.

“Even if he were, you’d just be a blurry shape to him anyway,” Baekhyun adds.

“You’ve already seen me naked, it’s not—” She sighs, dropping the sheet. “Be right back.” She slides off the mattress and makes to leave the room, but pauses first to pick up Baekhyun’s discarded shirt on the way.

Once she’s gone, Baekhyun chuckles fondly. “She’s really insistent about the whole… peeing after sex to avoid UTIs thing,” he says. “It’s cute.”

Kyungsoo hums, eyes still closed. One of his arms is under his head, the other setting on his naked abdomen. He’s the picture of tranquility. And maybe indifference.

“So uh.” Baekhyun wavers for a second. “What’s on your mind?”

“How dirty your sheets are now,” says Kyungsoo. “Too tired to care, though.”

Baekhyun bites his lip. “Okay, but—how was it, though?”

“What?”

“The—everything, all the sex just now, how was it?”

“Good,” says Kyungsoo. “You probably already know this, but you’re really good with—”

“I love you,” Baekhyun blurts out.

“—your—what?” Kyungsoo turns to him, eyes open and alert, shock coloring his features.

“Yeah, um.” Wow, bad timing. “Anyway. I think we should be boyfriends. So does Seulgi,” he adds. “And I think so do you? Unless I’m wrong. And if I am, just. Pretend this conversation didn’t happen.”

“Okay,” says Kyungsoo. “Not to pretending that didn’t happen, but the first part.”

“The boyfriends part?”

“Sure.”

“Sure,” Baekhyun repeats, making a face.

Kyungsoo laughs. “Yes,” he says, “I’d like to be boyfriends with you, Baekhyun.”

“Cool, so can I kiss you?”

Now it’s Kyungsoo who makes a face. “As much as I like your girlfriend, I really don’t want to taste her on your breath again,” he says. “That’s a boundary I have to set.”

“Noted,” says Baekhyun. “No eating pussy before trying to solicit kisses.”

“Okay, I’m setting another boundary right now, and it’s that I don’t want to hear you say ‘pussy’ ever again.”

Baekhyun huffs. “What do you want me to say? _Vagina_?”

“That’s terrible in a completely different way.”

“I take it back,” says Baekhyun, “I can’t date a man who doesn’t like the word ‘pussy.’”

“I don’t have anything against it,” says Kyungsoo, face and voice tinged with exasperation. “I specifically don’t like hearing it come from your mouth, because you make everything sound sleazy and disgusting.”

“There’s nothing sleazy about eating pussy!”

“God. If I kiss you, will you please stop?”

Baekhyun grins, rolling onto his side and pressing his lips to Kyungsoo’s. One of Kyungsoo’s hands settles on his hip and squeezes, and Baekhyun revels in the feeling once again of being touched by him in such a new and intimate way.

“Up for round two?” he murmurs.

“Think it would be round three at this point,” says Kyungsoo, pulling back somewhat. “Not now, though. I really am tired.”

“Too tired for me to suck you off?” Baekhyun clucks his tongue. “Man. That’s too bad.”

“Ah, let’s backtrack a little,” says Kyungsoo. “I’m completely awake and full of energy.”

Laughing, Baekhyun says, “No, you’re right, it’s break time.” He closes his eyes, leans his forehead against Kyungsoo’s. “Have to regain our energy through cuddling.”

“What about Seulgi?”

“She can be big spoon when she gets back.”

They stay like that, naked and clinging to each other. Seulgi comes back after a little while—too long for her to have just been using the bathroom, and Baekhyun halfway thinks her disappearance was intentional, giving them time alone. She stops at the foot of the bed, saying, “Hey, I’m gonna make coffee.”

“No, join our cuddle pile,” Baekhyun whines. Kyungsoo’s only contribution is a grunt that may or may not be an agreement.

“Babe, your sheets are gross and the room stinks,” she says plainly. “I’m really not staying in here longer than I have to right now.”

“She has a point,” says Kyungsoo.

“If you guys are gonna keep going, just make sure to open the window when you’re done so it airs out in here,” she says before disappearing from the room.

“I love her,” says Baekhyun.

Kyungsoo snickers. “She’s pretty amazing,” he says. “No complaints about sharing a boyfriend with her.”

“Good, or I’d have to… fight you or something. For her honor.”

“She could fight me for her own honor,” says Kyungsoo.

“Yeah, she probably could.” Baekhyun yawns. “Alright, nap time. Then round whatever.”

“Mmhm.”

He drifts off after that, heart full to bursting.

  


  


“A hundred percent?”

“Yep.”

Baekhyun furrows his brow. “Okay. Well. That’s fair.”

Seulgi pats his arm, still focusing on the movie in front of them. “He’s a great guy and I’m really happy for you two,” she says, “but he’s really not my type.”

“Yeah, I guess I can understand that.” Baekhyun sighs. “But I feel bad about you not having someone else, y’know? It’s so… unbalanced. Makes me feel like I’m being greedy or something.”

Now she looks at him, turning away from the grisly murder happening onscreen. “You want me to find a second person?” There’s something tentative in her voice, careful.

“Yeah, I mean. It’s only fair, right? But you don’t have to,” he says quickly. His attention is half on her, half on the movie. “Whatever you’re comfortable—” He cuts off with a yelp at a sudden jump scare, clutching at his chest. “ _Jesus_.”

“Well. Um.” She lets out a whooshing breath, like she’s steeling herself. “That was something I wanted to talk to you about, actually.”

“Yeah?” Baekhyun scrambles for the remote and quickly pauses the movie, more than happy to put it on hold for something less terrifying. “Do you have someone in mind?”

“Kind of. Actually, yeah.” She tucks her hair behind her ear. The picture of nervousness.

“And?” he prompts. “Who is it?”

“Someone at the studio.” Another deep breath. “She teaches modern dance.”

“She.” Baekhyun blinks. “You like girls?”

“Yeah.”

After a beat, he says, “I’m so glad neither of us is straight, holy shit.”

She lets out a surprised-sounding laugh. “Really?”

“It’s such a fucking relief.” He tugs on her arm to pull her closer, then plants a kiss just above her ear. “Now tell me about the hot girl you like.”

“I didn’t say she’s hot,” Seulgi mumbles, shrinking with embarrassment.

“But she is.”

She sinks further. “Yeah.”

Baekhyun laughs. “What’s her name?”

The answer comes out in unintelligible grumble.

“What?”

“Irene.”

“Irene,” says Baekhyun. “Does Irene like girls?”

“Yeah. Actually, um, she—asked me out, kind of?”

Another surprise. “Really? What’d you—”

“I said I wasn’t really available, but I’d, um, get back to her if I was?”

“Oh,” he says. A pause. “Well, you are.”

“I guess so,” she says.

“Hold on,” he says, “I have to text Kyungsoo.”

“Um. Why—?”

Phone already in hand, Baekhyun says, “I have to tell him my girlfriend’s gonna have a girlfriend. He’ll be happy for you. Probably also happy that I won’t pester you guys to try to date anymore.”

“You’re embarrassing,” she says.

“Yep!” he chirps, hitting _send_.

Minutes later, he gets a reply.

_Good, she deserves it._

Then:

_But if you’re thinking about trying to set up a double date or anything weird like that, the answer is no. Her answer will probably also be no._

That’s definitely true. Baekhyun sighs.

“I have a type,” he says.

“Oh yeah?”

“Cute people who are too nice and spoil my fun.”

She kisses his cheek. “Love you, too.” Then she reaches around to his other side and grabs the remote, unpausing the movie.

Terrible. But he wouldn’t have it any other way, he thinks.


End file.
